Infra-Red light corresponds to an electromagnetic radiation the range of which is used in telecommunication systems for carrying information data from a system to another while not being perceivable by a human being. As for example, some 3D device displays such as 3D TV comprises means for emitting a modulated IR light signal to open and close the left/right shutters of viewing glasses in synchrony with the corresponding left/right image displayed on the screen so that to allow the human visual system having a 3D perception of the displayed content. The Infrared light is used to transfer a synchronization signal from the display device to the glasses. It is understood that no single physical layer or communication protocol is used as a standard and that a multiplicity of solutions may exist. As for example, different 3D synchronization systems are using different IR light wavelengths in the range of 850 nm to 940 nm or in other range invisible for a human being. Moreover, some systems may comprise a transmission protocol using a carrier frequency whereas some others may use an unmodulated signal. Different and incompatible data signal timing protocols may also be implemented. As for example, some synchronized full time signal may be used whereas in some other embodiment a phase lock loop (PLL) may be used. Additionally, one, two or more IR emitters can be used to send the synchronization signal. Furthermore, some systems may isolate the IR emitters from the IR remote control receivers to avoid crosstalk while some others may put them right next to each other behind the same window. The multiplicity of solution is conducting the different systems to become not compatible with each other making as for example each 3D viewing glasses specific to a Brand or to a display screen. Furthermore, because some 3DTVs uses the same infrared wavelength as some remote control transceiver, typically 940 nm, interference problems may also occur in between.
A Consumer's Electronics Association's work group is investigating standardization for IR communicating device interoperability, including as for example viewing glasses for 3D TV synchronization. The communication standard should ensure that the infrared synchronization signal from the 3DTV to the active glasses is unaffected by the TV remote control signal and by other ambient optical noise sources, as well as for making remote control signals being unaffected by the synchronization signal itself. Among the possible solutions are included the selection of a specific wavelength for 3DTV infrared synchronizing signals so that to make it be different from the standard remote control wavelength signal. Another possibility is to make use of another carrier frequency, the allowable intensity of the synchronizing emitter reduced and the transmission protocol around a modulated signal is to be standardised. For example, the 3D synchronization may uses a short burst modulated signal at 25 kHz, a wavelength of 830 nm and a maximum emitter intensity of 1000 mW/sr.
An aim of the standardization of bidirectional communication through IR emitter-receivers would enable driving static devices such as:                Sound system        Glasses        Remote controllers        
Major problems to be solved would be:                Maximizing Interoperability        Avoiding interference        Preserving safety of humans        
The solutions expected would mainly focus on:                Making use of an IR electromagnetic radiation        Using some specific Modulation frequencies        Using diffused transmission or direct line-of-sight transmission        
In parallel, a new technology using IR light is emerging. It concerns three-dimensional imaging device systems the aim of which is to provide depth measurements of a scene. Such three-dimensional imaging device systems, such as a time-of-flight camera system (TOF camera), are device systems that create distance data with help of the TOF principle, and in which a receiver captures modulated light which has been emitted towards the scene by a light source such as an LED based illumination system and reflected therefrom. The TOF principle relies on the measured depth being determined by the time or phase difference in the overlap between the emitted modulated signal and the received modulated signal caused by the round trip time. The received signal is correlated or mixed with a copy of the emitted signal to obtain the time and the phase difference between them two and from which a distance can be determined. Typically, the camera device system comprises an illumination unit emitting in the IR domain a modulated signal at frequencies in the range of tens to hundreds of megahertz or more. An image sensing unit optimized for capturing the wavelength range emitted captures the scene in synchrony with the scene illumination; the sensing unit field of view being included in the illumination system optical engine frustrum.
TOF camera are built for use in several conditions, including at home for room or living-room experience such as for human to machine interactions and remote control if associated to method and systems such as a gesture recognition systems. TOF cameras are thus expected to coexist in the future within the same environment than the one comprising home standard telecommunications systems which are also using IR electromagnetic radiation.